This invention relates generally to systems and methods for processing workpieces, and more specifically, to an apparatus and method for detecting and removing undesirable material from workpieces that are carried on a conveyor.
The processing of meat, poultry, fish, and other food products has traditionally been a labor-intensive endeavor. In an effort to streamline operations, many food processors have turned to automated systems for detecting and removing undesirable material from food products, such as bones, fat, metal, glass, plastic, etc. For example, U.S. Pat. No. 4,970,757 to Heiland et al. describes an apparatus for automatic excision of bone from meat. The apparatus optically detects the location of bone in meat, and uses the location information to control a high-pressure water jet to automatically remove the bone. U.S. Pat. No. 5,334,084 to O""Brien et al. describes an apparatus for automatically trimming fatty tissue from animal carcasses. X-ray tubes are used to scan carcasses to obtain the width and location of fat seams. This information is input to a computer, which creates cutting paths for controlling a cutting device to segment the fatty tissue from the carcass. U.S. Pat. No. 5,902,177 to Tessier et al. describes an apparatus for automatically removing ribs from a flank. The apparatus uses an x-ray imaging unit to scan a flank to measure the thickness of ribs, and uses the thickness data to derive programmed cut data for controlling a cutting device to segment the ribs from the flank.
All of these systems process scanning data to obtain elaborate cutting paths for controlling a cutting device to segment undesirable material along its outline shape. Thus, the data processing involved is relatively complex, depending on the shape of the undesirable material, and, further, the controlled movement of the cutting device becomes complex to accurately trace the outline of the undesirable material. While these complex systems are certainly beneficial, they are expensive to install and operate.
There is an additional disadvantage associated with the existing systems. After undesirable material is segmented from a food product, both the segmented material and the food product are still carried on a conveyor in a mixture. The existing systems do not have any reliable mechanism for automatically offloading segmented undesirable material from a conveyor so that only the food products free from any undesirable material will continue on the conveyor for further processing, sorting, etc. Typically, segmented material is offloaded from the conveyor by hand to be placed on a separate take-away conveyor for transport to another location, perhaps to a discard bin. The manual offloading of segmented material is often unsatisfactory because it is difficult for the worker to visually distinguish segmented material from the rest of the workpieces repeatedly and for long duration with any accuracy. The difficulty is often exacerbated because processing of food products, especially fish, poultry, or meat, typically occurs at relatively low temperatures, in the range of 40 degrees. Performing the same repetitive offloading tasks in this cold environment can lead to physical ailments as well as create an undesirable work environment.
The present invention is directed to detecting and removing undesirable material from workpieces, including food products, which do not require relatively complex processing of scanned data or controlling of a cutting device. In addition, the present invention is capable of automatically offloading segmented undesirable material from a conveyor. Alternatively, the present invention is capable of rendering the segmented undesirable material visually distinguishable from the rest of the workpieces so as to minimize the mental and physical burden on the worker manually offloading the undesirable material.
The invention provides a method and system of detecting material desired to be removed from a workpiece that is carried on a conveyor. According to a first embodiment of the method, the workpiece is positioned adjacent a scanner and is scanned. Next, based on the scanning, it is determined whether the workpiece includes any undesirable material within. If so determined, a portion of the workpiece that contains the undesirable material is segmented into a visually recognizable shape, such as round, square, and triangular shapes. A worker stationed downstream along the conveyor can easily distinguish such segmented portion having a recognizable shape and remove it from the conveyor.
The present invention segments an undesirable material from a workpiece into a simple shape, instead of elaborately segmenting an undesirable material along its outline. Thus, the invention does not require relatively complex processing of scanned data or complex controlling of a cutting device.
In accordance with a further aspect of the invention, the location of the workpiece and the location of the segmented portion including undesirable material on the conveyor are tracked at all times. The location information may be used to automatically offload the segmented portion from the conveyor using a pickup device. The pickup device may then deposit the segmented portion onto a separate take-away conveyor for transport to a desired location. When a pick up device is used for automatic offloading, a portion containing undesirable material does not necessarily have to be segmented into a visually recognizable shape, because in this case manual labor will not be relied upon to offload the segments containing undesirable material.
In accordance with another aspect of the invention, an x-ray source is used as a scanner. An array of x-ray detectors is used to detect an intensity (or attenuation) of x rays after they have passed through the workpiece. The existence of an undesirable material is determined based on the detected attenuation of the x rays.
In accordance with yet another aspect of the present invention, an x-ray source and a camera, for example, a CCD (charge-coupled device), CID (charge injection device), or infrared (IR) camera, are combinedly used as a scanner. The thickness of a workpiece carried on a conveyor is measured. For portions of the workpiece that have a thickness above a predetermined value, undesirable material is detected based on the x-ray scanning. For portions of the workpiece that have a thickness below a predetermined value, undesirable material is detected using an image of the workpiece taken by the camera. This embodiment is useful for detecting undesirable material in young chicken breasts, for example, wherein both bone and meat portions have similar mass density values and thus x-ray scanning may not be effective in differentiating between the two, particularly in thin portions.
In accordance with still another aspect of the invention, a detected undesirable material may be cut out from the workpiece using a high-speed water jet, a laser, a rotary saw, a hacksaw, a guillotine, or a bandsaw.
According to a second embodiment of a system and method of the present invention for detecting material desired to be removed from a workpiece, first, a workpiece is positioned adjacent a scanner and is scanned. Then, existence of undesirable material in the workpiece is determined based on the scanning. Thereafter, if it is determined that undesirable material exists, the workpiece is marked with a visually recognizable sign. For example, a V-shaped notch may be cut out from the workpiece using a high-speed water jet. A worker working downstream of the conveyor may easily recognize the marked workpiece and remove it from the conveyor. Preferably, the worker deposits the removed workpiece onto a separate take-away conveyor for transport to another location, where a skilled worker may manually remove undesirable material from the workpiece.
According to a third embodiment of a system and method of the present invention for detecting material desired to be removed from a workpiece, first, a workpiece is positioned adjacent a scanner and is scanned. Then, based on the scanning it is determined if undesirable material exists within the workpiece. At the same time, the location of the workpiece on the conveyor is tracked. If it is determined that the workpiece includes undesirable material, the workpiece is automatically removed from the conveyor based on the known location of the workpiece. The removed workpiece may then be automatically deposited onto a separate take-away conveyor for transport to another location, where a skilled worker may manually remove undesirable material from the workpiece.
According to the first embodiment of the present invention, undesirable material is segmented into a visually recognizable shape, which minimizes the mental and physical burden on a worker in manually separating and removing segmented portions from the conveyor. This advantage is also provided by the second embodiment of the present invention, which marks a workpiece containing undesirable material with a visually recognizable sign so that a worker may easily pick out and remove the workpiece from the conveyor for further processing. Still further, in accordance with the present invention, segmented undesirable material or a workpiece determined to include undesirable material may be automatically offloaded from the conveyor. This eliminates the need to have workers stationed by the conveyor for the purpose of sorting and offloading segments or workpieces, which is highly desirable especially when the workpiece processing is carried out in a hazardous or uncomfortable, for example, a cold-temperature environment.